Automatic telephone system



A ril 13 1926. 1,580,490 I E. JACOBSEN AUTOMATIC TELEPHONE SYSTEM Filed Feb. 12. 1919 fnuenfur- Emzl Emubsen.

BIT

Patented Apr. 13, 192 6.

UNITED STATES 1,580,490 PATENT OFFICE.

EMIL JACOBSEN, 01' NEW YORK, N. Y., ASSIGNOR TO AUTOMATIC ELECTRIC INC., CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE. I

nuromn'rrc TELEPHONE SYSTEM.

Application filed February 12, 1919. Serial No. 276,824.

To all whom it may concem:

Be it known that I,"EMIL J AooBsEN, a citizen of the United States of America, and resident of the borough and county of Bronx, city'and State ofNew -York,' have invented certain new and q usefulrlmprovements in Automatic Telephone Systems, of which the-following is a specification."

My invention relates in general to automatic telephone systems, andmore" particularly to those .automatic.:systems which are commonlyknown as'ftwo wire systems, in which automatic switches at the exchange are controlled overthe two sides of the line in series. ii 1 More specifically, my invention has for its princi al object the provision ofiranfimprove connectorqswitch having a dimetively controlled primary and secondary motion. One of the details of improvement consists in the omission of the .usual side switch, the circuit changes which were formerly performed by this mechanism being in my improved switch performed by relays.

' In addition to the foregoing my invention 1s also concerned with an improved busy test arrangement involving a test relay, a wiper switching relay, a rivate wiper, a slow acting relay energize during the rotation of the switch to connect the private wiper to the test relay and when deenergized to conpect the private wiper to the switching reay. a

All the foregoing improvements together with others not now specifically mentioned, will be fully explained hereinafter, reference being had to the drawing.

In the drawing I have shownasub-stafiion A, a line switch C individual to the line of substation A, a connector switch D accessible to the line switch C, a line switch C individual to the line of substation A.

The substation A may be of any approved automatic type, such, for example, as the substation shown in the British patent to Martin, 1,419 of 1910. As represented herein, it

comprises essentially the receiver 4, transmitter 3, switch hook 7, ringer 5 and condenser 6. Being an automatic substation, it is also provided with a pair of impulse springs 8 and 9 which may be controlled by an impulse wheel through the medium of a finger hole dial (not shown).

The line conductors 10 and 11 of the substation A extend to the exchange where they show'honly diagrammatically, it being unless the armature of its associated line relay ;14'1s first-attracted toremovea stop from terminate in an individual line switch 0.

The line switch 0 may be of the general type of line switch shown in U. S. Letters Patent No. 1,126,727, granted February 2, 1915, to Dietl. Throu h the medium of the line switch 0, the line of substationA, when calling, is given ac'cess to a plurality- 0f trunk lines extending to connector switches.

Thejlme switches of the drawings are der'stoodthat the armatures of the line relays'14 and the switching-relays 16 have certain interlocking features, that is, the armature-"of relay 16 cannot be fully attracted unthe path "of the armature of rela 16. It

will therefor'ebe understood that w en a call part way until it meets thestop. attached to the armature of relay 14. In this way the relay 16 will operate only to disconnect the line relay and ground from the line circuit without switching the line through to the wipers. In a call from a'line, however, re-

lay 14 is energized first removing the stop i from the .ath of the armature of relay 16, so that w en relay 16 is energized it will. only attract its armature.

One of the trunk lines to which the line switch C has access is shown extending to the connector switch D; The connector switch D may be of the general type of con,-

nector switch disclosed in U. S. Letters Patf ent No. 815,176, granted March 13,1906, to'

Keith, Erickson, and Ericksornexcept' that the side switch and. private magnet are omitted and the circuits are revised'in accordance with the two wire system of con-' may be in all respects similar to the subzta- 100 tion A and the line switch 0.

While I have shown throughout the drawing a. plurality of batteries, it is to be understood that there is preferably but one battery having its positive pole grounded. As-- 105 sociated with the connector D, I have shown a ringing equipment H, and a busy signalling machine I. This apparatus may be the usual type, such as is found in well known telephone systems.

Havin briefly described the apparatus involved, will now roceed to explain more in detail the 0 eration of the same.

When the su criber at substation A removes his receiver, a circuit is clo:ed at the switch hook springs for the line relay 14 of the switch C in series with the line circuit. Relay 14, upon energizing, closes a circuit at springs 15, including switching relay 16, and the rotary magnet 17 in series, and at the same time prepares a circuit for the magnet 17 at springs 18 to the private wiper 20. Suppose the trunk line upon which the wipers 19, 20, and 21 is busy, then a ground potential is present on the private contact corresponding to that trunk. This ground otential will short the high resistance re ay 16 and energize the rotary magnet 17 to step the wipers to the contacts of the next trunk line. It this trunk line is busy, the rotary magnet will again be energized, and this operation will continue until an idle trunk is reached, at which time there will be no potential present atthe contact which the private wiper meets. Relay 16 will be no longer shorted out and will immediately energize over the series circuit hereinbefore traced, to extend the line of substation A to a trunk line leading to a connector switch.

Suppose the first idle trunk line is the trunk line 22, 23, and 24 leading to the connector switch D. Relay 16, upon energizing, closes a circuit for the double Wound line relay 25 of the connector D, in series with the line circuit and wipers 19 and 21. Relay 25, upon energizing, closes a circuit for the slow acting release relay 26. Relay 26, upon energizing, closes a holding circuit for the relay 16 of the line switch C, which may be traced as follows: from ground at G springs 33, conductor 23, wiper 20, springs 34, winding of relay 16, winding of magnet 17 to battery. Since the line relay 14 is slow acting, it retains its armature to maintain the winding 16 energized until after the above holding circuit has been established. A branch of the holding circuit extends by Way of conduc-v tor 35 to multiple test contacts in the banks of connector switches having access to the line of substation A. By placing a ground potential on these test contacts, the said line is made busy.

The foregoing operations have occurred in response to the removal oi the receiver at now has substation-A. The calling subscriber may proceed to manipulate his calling device in accordance with the first digitof the desired number, thereby producing in the usual and well known manner a series of interruptions in the line circuit. At each interruption the line relay 25 deenergizes momentarily and sends an impulse of current to the vertical magnet 36' over the following path: From ground at G through springs 27 and 29, springs 30 and v 31, off normal springs 37 and 38, winding of low resistance slow actingrelay 39, and winding'of vertical magnet 36 to battery. In response to these impulses the vertical magnet operates to raise the shaft step by step until the wipers 40, 41, and 42 arrives at the horizontal level of bank contacts in which are located the terminals of the called lines. (It is assumed that theline of substation A is the called line.) Relay 39 is energized in series with the vertical magnet and retains its armature during the series of impulses, thereby preventing the opening of the vertical magnet circuit by the shifting of the off normalsprings which operation occurs as soon as the shaft leaves normal position. f v

The calling subscriber may now-call the units or final digit in .the desired number, thereby producing as before a series of interruptions in the line circuit. Now, however, the off normal springs 37 and 43ai-e closed, and the relay 39 having deenergized, the line relay transmits a series of impulses to the rotary magnet 44, over the following path: ground at G, springs 27 and 29, springs 30 and 31, off normal springs 37 and 43, springs 45, springs 46, springs 47, winding of rotary magnet 44 to battery. The rotary magnet responds to the impulses of current in the circuit to rotate the wipers 40, 41, and 42 until they arrive at the bank contacts 48, 49, and 60, which form the terminal of the line of substation A. It will be noted that a branch of the rotary magnet circuit extends through the winding of the 'slow acting relay 51 to battery. It follows that relay 51 will be energized in parallel with the rotary magnet during the rotation of the switch, and since it is slow acting, it retains its armature attracted during the series of impulses to the rotary magnet. When the relay 51 is energized,the private wiper 41 is connected to the winding of test relay 56 as follows: wiper 41,"sp'rings 52 and 54, sprin s 57, winding of relay 56 to battery. omentary energizations of relay 56 due to the wiper 41 passing over busy contacts (if there be any such contacts in its path) are of no consequence because of the alternative circuit for the rotary magnet by way of springs 58 of the relay 51. Y J

The switch wipershaving been rotated into connection with the terminals of the desired line, the operations now depend on whether or not that line is busy. Assuming the line to be'idle, the test contact 49' will be clear of ground, the relay 56 will remain inoperative, and upon the deenergization of relay 51 the following circuit will be closed.

Grounded conductor 59, springs 61 and 60, upper winding of relay 63, sprin '53 and 52, wiper 41, test contacti'49, winding of switching rela 16', and winding of rotary magnet 17 of ine switch C to battery. Relays 63 and 16 are energized in series, the latter operating to clear the line of substation A from battery and ground connections in the line switch. Belay 63, upon energizing, closes a locking circuit for itself by way of grounded conductor 64, springs 65 and 66, lower winding of relay 63 to battery. At the same time at sprin s 65 and 67 the conductor 64 is connected irect to the test wipers 41. Further results of the energization of relay 63 are the breaking of the rotary magnet circuit at sprin s 47, and the breaking of the previously described test circuit at springs 57.

A still further result of the energization of relay 63 is the closure of a signalling circuit at springs 67 and 68, which may be traced as follows: ground at G, generator Gen, springs 70, springs 71 and 72, springs 68, wiper 42, conductor 11, ringer 5 ,.condenser 6, conductor 10, contact 48,- wiper 40, springs 67, springs and 74 upper winding of relay 77 to battery. At the connector D, by the operation of the interrupter appara tus, the generator Gen is intermittently-cut out of the ringing circuit and booster battery substituted therefor. The ring out off relay 77 is so adjusted that it will operate on the current from generator Gen and the exchange battery in series when the direct current bridge is closed at substation A or on current from the exchange battery and the booster battery in series under the same condition; but it will not operate from generator current above when the condenser at,

, scriber may detect the operation of the ringing apparatus by the tone which he gets by induction between the windings of relay 77. To proceed, relay 77, upon energizing, disconnects its upper winding and the interrupter apparatus at springs 74 and 75 and springs 71 and 72, and at springs 75 and 76 and springs 72 and 73, completesthe talking circuit through the connector D. The back bridge relay is now energized in series over the called line circuit and reverses, in the usual and well known manner, the incoming line conductors as regards their connection -to the windings of the line relay 25. This 'potential upon it.

causes a reversal of current in the calling line which may operate a meter (not shown). Talking battery for the transmitters at substation A is supplied from the windings of the line relay 25, while the transmitter at substation A is supplied from the winding of relay 79. The path for voice currents is indicated by heavy conductors, and will be geadily understood without further explanaion.

When the conversation is finished both subscribers will replace their receivers. By the replacement of the receiver at substation A the circuit of the answering bridge relay 79 is broken. Relay 79, upon deenergiz mg, again reverses the incoming line conductors as regards their connections to the windings of the line relay 25, also closes a point in the circuit-of the release magnet at springs 81. By the replacement of the receiver at substation A the circuit of the line relay 25 is broken. Upondeenergizing, line relay 25 breaks the circuit slow acting release relay 26, also sends an impulse of current to slow relay 51 over the circuit hereinbefore traced. Relay 26, uplon deenergizing, removes ound from t e holdin circuit extending ackto the line switch a and also closes a circuit for the release magnet 80. By the former operation the relay 16 of the line switch C is allowedto restore its springs to normal. The energization of the release magnet 80 results in the restoration of the connector to normal.

It is to benoted, however, that should the calling subscriber replace his receiver first, the holding circuit for the relay 16 is broken at springs 33, and, assoon as the relay 51 deenergizes, ground potential is again applied to the test contact 33 over the following circuit: from G springs 82, springs 83, springs 84, conductor 64, springs 65 and 67, springs 52 and 55, upper winding 'of relay 63, springs 60 and 61 to the test contact 23.

It will now be described how the connector D operates when it is attempted to establish connection with a busy line. For this purpose it will be assumed that the line of substation A was busy when called, in which case the test contact 49 would have a ground Under these circumstances, when the connector wipers 40, 41, and 42 are rotated into engagement with the contacts 48, 49, and 50, the relay 51 is energized during the rotation as previously described. As soon as the test wiper 41 arrives at the test contact 49 the relay 56 will be energized over a circuit hereinbeforc traced with results which will now be pointed out. At springs 61 and 60 the grounded conductor 59 is disconnected from the upper winding of relay 63, and at springs 61 and 62 a locking circuit is prepared which, upon the deenergization of relay 51, is completed over the following pathzgrounded conductor 59, springs 61 and 62, springs 55 and 54, springs 57, winding of relay 56 to battery. Relay 56 is thus locked in energized position until the connector is released, and the relay (33 is prevented from energizing to establish connection with the called line. Further results of the operation of relay 56 at this time are the opening of the rotary magnet circuit at springs 46, and the connection of a lead from the busy signaling machine I to the lower heavy line conductor at springs 81. By the transmission of a distinctive tone to the calling subscriber, he is informed that the line with which he is attempting to obtain connection is busy, whereupon he will replace his receiver, and the line switch and connector will be released as previously explained.

Having described my invention, what I consider to be new and desire to have protected by Letters Patent will be pointed out in the appended claims.

lVhat I claim as my invention is:

1. In a telephone system, a link circuit having talking conductors and terminating in an automatic switch, means for operating said switch to connect said conductors with the conductors of acallcd line, a switching relay controlling normally open contacts in said link conductors, a test relay for testing called lines, a test wiper, a slow acting relay energized during the operation of said switch and for an instant thereafter, and circuit connections whereby when said slow acting relay is energized the test wiper is connected to said test relay through contacts of said slow relay and whereby when said slow acting relay is deenergized said test wiper is connected to said switching relay.

2. In a telephone system, a linkcircuit having talking conductors and terminating in an automatic switch, telephone lines accessible to said switch, an operating magnet for said switch, a circuit'for transmitting impulses of current to said magnet, whereby connection may be established with a desired one of said lines, a test relay for determining the idle or busy condition of a called line, a test wiper, and a slow acting relay ener-f gized by said current impulsesto connect said test wiper to said test relay while ener gized.

3. In a telephone system, a link circuit,

having talking conductors and terminating in an automatic switch, telephone lines accessible to said switch, an operating magnet for said switch, a circuit for transmitting impulses of current to said magnet, whereby connection may be established with a desired one of said lines, a test relay for determining the idle or busy condition of a called line, a test wiper, a slow acting relay energized responsive to said current impulses to connect said test wiper to saidtest relay, a

switching relay controlling normally open contacts in said talking conductors, and a circuit for said switching relay including said test wiper, said circuit controlled jointly by said test and slow acting relays.

4. In a telephone s stem, a connector switch including two tal ing conductors and two line wipers, a called line terminating in bank contacts accessible to said wipers, means for operating said switch to cause said wipers to connect with the called line via said contacts, a test wiper for said connector and a test contact for the called line engagedby said test wiper when the connection is established, a cut-off relay for the called line having one terminal connected to said test contact and the other connected to a grounded battery, a switchingrelay for connecting said ta king conductors to said line wipers having one terminal connectedto ground before the switch is operated, the other terminal being disconnected from said test wiper while the switch is operating, and means for connecting the said other terminal of said switching relay to said test wiper when the connection is established, thereby energizing said relays in a series circuit over the said test wiper and test contact 5. In a telephone system, a connector switch including two talking conductors and v two line wipers, a called line terminating in bank contacts accessible to said wipers, means for operating said switch to cause said wipers to connect with the called line via said contacts, a test wiper for said connector and a test contact for the called line engaged by said test wiper whenthe connec:

tion is established, a cut-oii relay for the called line having one terminal connected to said test contact and the otherconnected-to a grounded battery, a switching relay for connecting saidtalking conductors to said line wipers having one terminal connected and a test wiper, a motor magnet for causing said wiper to advance and wipe over a plurality of said contacts successively, a circuit for operatingsaid magnet, a test relay,

"telephone-systems, a bank of test contacts another relay energized while said motor magnet is operating,contacts closed by the energiation of said othergrelay for connect ing said test wiper to said test relay, contacts on said test relay for opening the motor magnet circuit, and contacts on said other relay for shunting saidfcontacts on the test relay. v

telephone systems,

7. In a, connector switch for automatic means including a motor magnet for causing the connector to locate and connect with a called line, atest relay for determining the idleor busy condition ofthe called line, a second relay controlling said test relay to render the same operative before the called line is located, thereby causing said test relay to taste plurality of other lines during the operation of the switch,

means controlled by said test relay for preventing the operation of said magnet, and means controlled by said second relay for nullifying the efiect of said preventing means.

Signed by me at New York, New York County, State of New York, this 4th day of February, 1919.

EMIL JACOBSEN. 

